Potential for improving the rubidium frequency standard with a novel optical pumping scheme using diode lasers

It is experimentally demonstrated that, using diode lasers for optical pumping and RF π-pulses for population transfer, nearly all of the ground state Rb atoms in a vapor cell can be concentrated into one of the two M_F = 0 sublevels. The fractional population difference Δ between the two M_F = 0 levels can be made as high as 1. This should result in a very significant improvement (about a factor of 100) in the S/N over the conventional discharge-lamp-pumped rubidium frequency standards (RFSs). This would lead to a substantial improvement in the short-term stability of the RFS. This is a pulsed population transfer scheme. The microwave interrogation takes place in the absence of strong pumping light. This has the potential for eliminating the light shift and thereby improving the long-term frequency stability of a an RFS